The use of water-swellable, generally water-insoluble absorbent materials, commonly known as superabsorbents, in disposable absorbent personal care products is known. Such absorbent materials are generally employed in absorbent products such as diapers, training pants, adult incontinence products, and feminine care products in order to increase the absorbent capacity of such products, while reducing their overall bulk. Such absorbent materials are generally present as a composite of superabsorbent particles (SAP) mixed in a fibrous matrix, such as a matrix of wood pulp fluff. A matrix of wood pulp fluff generally has an absorbent capacity of about 6 grams of liquid per gram of fluff. The superabsorbent materials (SAM) generally have an absorbent capacity of at least about 10 grams of liquid per gram of SAM, desirably of at least about 20 grams of liquid per gram of SAM, and often up to about 40 grams of liquid per gram of SAM. Clearly, incorporation of such absorbent materials in personal care products can reduce the overall bulk, while increasing the absorbent capacity of such products.
Capillary driven fluid distribution within the absorbent material is typically hindered due to the presence of the superabsorbent. The fluid distribution may be enhanced by optimizing various superabsorbent physical and functional attributes; however, such modifications traditionally have reduced the pressure driven (forced flow) fluid intake performance of the absorbent core.
Different superabsorbent particle sizes have been used to enhance different composite performance attributes, such as composite intake and distribution. Large particles have been used to create larger voids when swelling to improve fluid intake rate; however, these particles negatively affect fluid distribution. Smaller particles have been used to create smaller voids when swelling to improve capillarity and rate of fluid distribution. However, neither approach has been able to improve one of the properties of intake or distribution without negatively affecting the other property.
What is needed in the art is a composite material comprising superabsorbent material, wherein the composite material has improved intake, as well as, improved distribution.